1. Field of the Invention
This invention relates broadly to medical devices. More particularly, this invention relates to surgical filter basket devices adapted to retrieve emboli and thrombi in the venous system.
2. State of the Art
Several filter basket devices have been developed for capturing emboli which might be generated during angioplasty or stenting. All such known devices have a shaft which consists of a wire-like central member and a coaxial tubular member which surrounds the central member. A basket (or umbrella) is provided at the distal ends of the central member and stored within the distal end of the tubular member, when not deployed. The basket is deployed by moving the central member distally relative to the tubular member to force the basket out of the tubular member.
In some cases, see e.g., U.S. Pat. No. 6,336,934 to Gilson et al., the basket is anchored to the central wire. In other cases, such as shown in U.S. Pat. No. 6,325,815 to Kusleika et al., the basket floats on the wire, and the wire engages the basket by means of “stops” which come into contact with the basket when the wire is advanced or withdrawn through the sheath, which cause the basket to be pulled from the stored position to the expanded (released) position and vice versa. In all cases, the basket is deployed by moving one or more wires on which the basket is mounted relative to the sheath to force or permit the basket to expand.
The use of the sheath results in such a filter basket device having a minimum diameter no less than the diameter of the sheath, and the sheath must be of sufficient size to receive the wires therethrough. It is important to keep the diameter as small as possible, as the device must be introduced through the small lumen of a guiding catheter to the site of operation. Moreover, the filter basket device may need to be introduced together through the lumen along with other interventional catheter devices, such as angioplasty balloons, stent deployment systems, and stems.